1. Technical Field
The present invention relates to a liquid-ejecting head and a liquid-ejecting apparatus each including a piezoelectric element for altering the internal pressure of a pressure-generating chamber in communication with a nozzle opening. The invention also relates to the piezoelectric element and a piezoelectric material.
2. Related Art
One representative example of liquid-ejecting heads installed in liquid-ejecting apparatuses is an ink jet recording head. The ink jet recording head has a diaphragm as part of a pressure-generating chamber. The pressure-generating chamber communicates with a nozzle opening through which ink droplets are ejected. The diaphragm is deformed by the action of a piezoelectric element to pressurize ink in the pressure-generating chamber, causing ink droplets to be ejected through the nozzle opening. Examples of the piezoelectric element installed in the ink jet recording head include longitudinal vibration piezoelectric elements and flexural vibration piezoelectric elements. A certain piezoelectric element of the longitudinal vibration mode is manufactured by fixing a piezoelectric-element-forming member (a piezoelectric diaphragm) to a fixed substrate and cutting the piezoelectric-element-forming member in a comb-like shape with a wire saw. The piezoelectric-element-forming member includes a common internal electrode and individual internal electrodes stacked with a piezoelectric material interposed therebetween (see, for example, JP-A-11-129474).
The piezoelectric material used for such a piezoelectric element requires excellent piezoelectric characteristics (a large strain). One representative example of the piezoelectric material is lead zirconate titanate (PZT).
In recent years, however, from an environmental point of view, there has been a demand for piezoelectric materials of low lead content. Thus, various piezoelectric materials having an ABO3 perovskite structure have been proposed as lead-free piezoelectric materials.
However, lead-free piezoelectric materials produce a smaller strain than PZT. Thus, there is a demand for piezoelectric materials that can produce a large strain and have excellent piezoelectric characteristics.
Such problems exist not only in ink jet recording heads but also in liquid-ejecting heads for ejecting liquid other than ink.